The invention relates to a practice projectile for target practice, which corresponds in shape and weight to a normal combat projectile, particularly to a sub-caliber combat projectile, and which upon impact disintegrates at preset breaking points.
Practice projectiles for target practice are used for the training of soldiers in the use of a firearm and should therefore reproduce the properties of normal combat projectiles as accurately as possible, if they are to serve their purpose as regards training. This applies both to the external ballistics by which the trainee's acquisition of the aiming reflexes, and any necessary correction reflexes are governed and to the operation and use of the weapon. At present the training of soldiers in the use of firearms is carried out to the maximum range of the type of weapon in use. It is true that the firing is usually effected at an angle of elevation which does not provide the maximum range, but there is a possibility that the shot will ricochet, thus reaching a distance almost equal to the maximum range. This applies in particular to sub-caliber combat projectiles constructed as "weight" projectiles for tank-carried guns. The corresponding practice ammunition in such cases is modified in the manner required to ensure that after the combat distance has been exceeded the projectile is strongly braked by acrodynamic measures; a limited safety range on both sides is required; however, since the practice projectile lands flat on hard ground at a short distance it is likely to ricochet in the transverse direction with energy which is hardly reduced at all and must nevertheless be prevented from going beyond the safety margin.
German Exam. Patent application 23 09 589 (which corresponds to U.S. Pat. No. 3,898,933) describes a practice projectile of the type described hereinbefore, designed for subcaliber ammunition contained in a cartridge. This practice projectile is required to disintegrate both when hitting the target, without destroying the latter, and when landing flat on the ground. It consists of a metallic projectile casing with a filling of powder mixed with a polymerizable product, the dimensions required for the metal projectile casing being such that the preset breaking line, upon the impact of the practice projectile, takes the form of a tapering breaking zone positioned radially of the pulverous filling compound which thereafter emerges. The construction of the known practice projectile is relatively complicated, so that it is expensive to manufacture. Furthermore, it is not immediately clear how a preset breaking line can be provided which will stand up to the stresses undergone by it when the projectile is being fired and also during its flight and nevertheless will cause the projectile to disintegrate as soon as it makes impact on the hard ground; this is particularly true, since the projectile is also required to disintegrate by itself without causing damage to the actual practice target upon impact thereon.